The major redesign of Content Manager Version 8 takes advantage of database stored procedure calls, which reduce the amount of back-and-forth communication between the client application or mid-tier application and the database. In a single stored procedure request, the client can initiate a long series of database queries and changes that might otherwise have taken many client-to-database requests. This provides a major performance boost, especially over low-bandwidth connections. Although this reduces the workload, it is still good to avoid any unnecessary client requests and data transfer to or from the servers. To monitor the interactions with the database, you can run the DB2 CLI or JDBC traces from the client or mid-tier server and see the calls and response times. By default, these facilities are disabled and use no additional computing resources. When enabled, the trace facilities generate one or more text log files whenever an application accesses the appropriate driver (DB2 CLI or DB2 JDBC). These log files provide detailed information about: The order in which CLI or JDBC functions were called by the application The contents of input and output parameters passed to and received from CLI or JDBC functions The return codes and any error or warning messages generated by CLI or JDBC functions DB2 CLI and DB2 JDBC trace file analysis can benefit application developers in a number of ways. First, subtle program logic and parameter initialization errors are often evident in the traces. Second, DB2 CLI and DB2 JDBC traces might suggest ways of better tuning an application or the databases it accesses. The configuration parameters for both DB2 CLI and DB2 JDBC traces facilities are read from the DB2 CLI configuration file db2cli.ini. By default, this file is located in the \sqllib path on the Windows platform and the /sqllib/cfg path on UNIX platforms. You can override the default path by setting the DB2CLIINIPATH environment variable. On the Windows platform, an additional db2cli.ini file might be found in the user’s profile (or home) director if any user-defined data sources are defined using the ODBC Driver Manager. This db2cli.ini file will override the default file. To view the current db2cli.ini trace configuration parameters from the command line processor, issue the following command: db2 GET CLI CFG FOR SECTION COMMON
Chapter 5. Designing and configuring for performance
139